support ^(?:/p/|/a/|/) git url

Change-Id: I286938b76604c50afda91fa7f1499f4ebbf7a9c0
(cherry picked from commit dbd795ee172dd532656ddc758f175632c627ec5f)
diff --git a/src/backend.c b/src/backend.c
index 92d1016..8720502 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -256,7 +256,9 @@
                         end--;
                 }
                 if (p != NULL && (!strncmp(p, "git-receive-pack", 16) || !strncmp(p, "git-upload-pack", 15))) {
-                        // we have git request here
+                        if (!strncmp(start, "/a/", 3) || !strncmp(start, "/p/", 3))
+                                start += 2;
+			// we have git request here
                         // get rid of redundant '/'
                         while ((end - start) > 1 && *(start+1) == '/')
                                 start++;
@@ -265,7 +267,9 @@
                         // get rid of trailing ".git"
                         if ((end - start) > 4 && strncmp(end-4, ".git", 4) == 0)
                                 end -= 4;
-
+                        // get rid of redundant '/'
+			while ((end - start) > 1 && *(end-1) == '/')
+                                end--;
                         hash = gen_hash(px, start, (end - start));
                 } else {
                         if (px->lbprm.arg_opt3 > 0){